One or more low carbon atom fluorocarbons of usually 7 carbon atoms or less are contained on a polymer generally having polar groups. The fluorocarbons generally exist as side chains with at least 25% of the hydrogen atoms being replaced by fluorine atoms. The polymer of the present invention is found unexpectedly to be an effective wetting, or flow, or leveling agent while producing little foam.
U.S. Pat. No. 3,859,253 to Bourat et al. relates to polyoxetanes comprising a plurality of repeating units wherein the chain oxygen atoms of each recurring unit is attached to a chain methylene group of an adjacent recurring unit with, in addition, cross-linking via the other free valencies when the polymer contains repeating units.
U.S. Pat. No. 5,068,397 to Falk et al. relates to tris-perfluoroalkyl terminated neopentyl alcohols of the formula (Rfxe2x80x94Enxe2x80x94Xxe2x80x94CH2)3CCH2OH prepared from halogenated neopentyl alcohols and thiols of the formula Rfxe2x80x94Enxe2x80x94SH, amines of the formula Rfxe2x80x94Enxe2x80x94NHxe2x80x94R, alcohols of the formula Rfxe2x80x94Enxe2x80x94OH, and perfluoro-acids or amides. The alcohols react with isocyanates to prepare urethanes; with acids or derivatives to prepare esters or carbonates; with epoxides to form ethers. Further, they may be converted to halide intermediates. The products all contain the residue of at least one Rf-neopentyl alcohol containing three perfluoroalkyl hetero groups.
U.S. Pat. No. 5,674,951 to Hargis et al. relates to coating compositions which use a polyoxetane polymer having xe2x80x94CH2xe2x80x94O xe2x80x94CH2xe2x80x94Rf side chains where Rf is a highly fluorinated alkyl or polyether. The coating compositions use polyisocyanates to create isocyanate terminated polymers from the poly(oxetane) and from various polyols from alkylene oxides or polyester polyols. These can be reacted together to form block copolymer structures or can be linked together when the coating is crosslinked. A preferred method is to use blocked isocyanate groups. Another preferred embodiment is to use the composition as an abrasion resistant coating for glass run channels.
U.S. Pat. No. 5,807,977 to Malik et al. relates to fluorinated polymers and prepolymers derived from mono-substituted oxetane monomers having fluorinated alkoxymethylene side-chains and the method of making these compositions. The mono-substituted fluorinated oxetane monomers having fluorinated alkoxymethylene side-chains are prepared in high yield by the reaction of a fluorinated alkoxide with either 3-halomethyl-3-methyloxetane premonomers. It also relates to copolymers of oxetane and tetrahydrofuran.
U.S. Pat. No. 5,998,574 to Fishback et al. relates to a polyol composition comprising: (A) a polytetramethylene ether glycol, and (2) a difunctional active hydrogen compound-initiated polyoxyalkylene polyether polyol having a degree of unsaturation of not greater than 0.04 milliequivalents per gram of said polyether polyol.
U.S. Pat. No. 6,020,451 to Fishback et al. relates to a polyol composition comprising: (A) a polytetramethylene ether glycol, and (2) a difunctional active hydrogen compound-initiated polyoxyalkylene polyether polyol having a degree of unsaturation of not greater than 0.04 milliequivalents per gram of said polyether polyol.
U.S. Pat. No. 6,127,517 to Koike et al. relates to the polymerization of hexafluoropropene oxide (HFPO) in a polymerization initiator solution of the formula: CsCF2xe2x80x94Rfxe2x80x94CF2OCs wherein Rf is a perfluoroalkylene group which may have an ether bond in an aprotic polar solvent provided that the initiator solution is first treated by adding a perfluoroolefin thereto at a sufficient temperature for the removal of protonic substances, cesium fluoride and hydrogen fluoride. This simple treatment restrains chain transfer reaction, and the process is successful in producing a difunctional HFPO polymer having a high degree of polymerization while suppressing formation of a monofunctional HFPO polymer.
U.S. Pat. No. 6,168,866 to Clark relates to a curable fluorine-containing coating composition comprising: (i) an amino resin; (ii) an addition fluoropolymer comprising a copolymer of a fluorinated monomer having a fluorocarbon group of at least 3 carbons, and a non-fluorinated monomer having a crosslinking group capable of reacting with said amino resin at elevated temperatures; and (iii) a hardening agent capable of crosslinking with said amino resin at elevated temperatures.
Heretofore, non-polymeric molecules containing fluorinated and polar groups were used as wetting, or flow, or leveling agents; however, many of these materials have been shown to bioaccumulate thereby greatly limiting their utility.
The partial or fully fluorinated short carbon atom side chain containing polymers of the present invention unexpectedly have good wetting, or flow, or leveling properties. The types of polymers are numerous and include polymers derived from cyclic ethers, poly(acrylates), poly(methacrylates), hydroxyl terminated poly(acrylates) or poly(methacrylates), polyolefins, polymers derived from vinyl substituted aromatic monomers such as styrene, polyesters, polyurethanes, polyamides, polyimides, polysiloxanes, and the like with polyoxetane being preferred. The polymers have at least one group that is polar which can be an anionic group, a cationic group, or a nonionic group. The polymer can also be amphoteric containing both anionic and cationic groups.
Furthermore, the polymers of the present invention can be caused to react with another monomer or with another polymer to impart effective wetting, or flow, or leveling properties to a coating prepared therefrom. Alternatively, the polymers of the present invention can be used as an additive with other polymers, copolymers, compositions, etc. to provide improved wetting, or flow, or leveling properties. Compared to molecules used typically as wetting, or flow, or leveling agents, the materials set forth in the present invention have relatively little propensity to cause foaming. This is often a desirable attribute of a wetting, flow, or leveling agent.
The fluorinated short carbon chain compounds of the present invention are generally located on polymers as side chains thereof. These polymers, which contain one or more polar groups are generally dispersible or soluble in water and various hydrocarbon solvents and unexpectedly function as wetting, or flow, or leveling agents providing good optical properties to a coating such as high gloss and good distinctness of image, and thus can be blended with a wide variety of solutions, waxes, polishes, coatings, blends and the like.
Polymers of the present invention contain fluorinated carbon groups generally represented by the formula Rf. The Rf groups can be part of the monomer which is reacted to form the polymer or they can be reacted with an already formed polymer. Alternatively, a polymer containing a Rf group such as a fluorinated polyoxetane can be reacted with a polymer or monomer to form a copolymer which thus contains a plurality of pendant short chained Rf groups thereon. Examples of a non-Rf containing copolymer portion are various cyclic ethers, various polyesters, various acrylic polymers, various polysiloxanes, various polyamides, various polyurethanes, and various polymers made from vinyl substituted aromatic monomers.
A wide variety of fluorine-containing polymers can be utilized as generally set forth by the following description:
The polymer can be comprised of repeat units (with repeat units being greater than or equal to 2) of a variety of monomers including cyclic ethers, acrylates, olefins and vinyl moieties. The most preferred monomers are cyclic ethers (including fluorinated cyclic ethers such as those based on hexafluoropropylene oxide) such as oxetanes, and oxiranes. Other preferred monomers include acrylates, vinyls including styrenics, silanes, and siloxanes, as well as polyester forming monomers, polyamide forming monomers, polyimide forming monomers, and polyurethane forming monomers. The polymer may be of the copolymer type comprised of, but not limited to, the aforementioned monomers. The copolymer may be of the statistical or block type. The average degree of polymerization should be at least 2 as to about 100 or 200, and preferably from 2 to about 10 or 20, or 30.
The polymer may contain more than one Rf type of group and the types of Rf, independently, can be the same or different and are fluorinated alkyl groups such as a linear alkyl group having a main chain of about 7 carbon atoms or less, desirably from about 1 to about 5 or 6 carbon atoms, and preferably 2, 3, or 4 carbon atoms. The Rf alkyl group can be branched. When branched, the longest chain is composed of 7 carbon atoms or less with each branch containing a maximum total of 3 carbon atoms or less. Rf whether linear or branched has at least one carbon atom bonded to at least one fluorine atom. The total amount of fluorine atoms in each Rf group is generally at least 10% or 25%, desirably at least 50% or 75%, and preferably at least 80%, 85%, 90%, or 95%, or even 100% (perfluorinated) of the non-carbon atoms with any remaining non-carbon atoms or nonfluorine atoms being H, or I, or Cl or Br.
The pendant or side chain Rf group can be present on all the monomers comprising the polymer or on a selected few with a preferable range of about 50 to 100% of monomers comprising the polymer containing a pendant or side chain Rf group. A preferred polymer contains one Rf group per repeat unit. The Rf group can be bonded directly to the polymer, or desirably is covalently bonded through another linking moiety or group bonded to the polymer such as a hydrocarbyl, a sulfonyl, an ester, an alkyl sulfide, or the like. A desired moiety is alkyl ether such as
xe2x80x94CH2xe2x80x94Oxe2x80x94(CH2"Parenclosest"nxe2x80x83xe2x80x83(Formula 1)
where n is from about 1 to about 6 with 1 or 2 being preferred.
Examples of polar groups covalently bonded to the polymer include anionic groups such as xe2x80x94CO2xe2x88x92 (Carboxylate), xe2x80x94SO3xe2x88x92 (Sulfonate), xe2x80x94OSO3xe2x88x92 (Sulfate), xe2x80x94OPO3xe2x88x92 (Phosphate), and xe2x80x94ONO2xe2x88x92 (Nitrate). Cationic counterions groups associated with the just noted anionic polar groups include Li+ (lithium), Na+ (sodium), K+ (potassium), Cs+ (cesium) and ammonium salts of the general formula, NH4xe2x88x92XRX+ where R is typically a hydrocarbyl radical (e.g. a hydrocarbon radical) having from 1 to 10 or 18 carbon atoms and X is 0 to 3, or a quaternary ammonium salt.
Cationic polar groups covalently bonded to the polymer include NH4xe2x88x92xRx+ (Ammonium), or a quarternary ammonium and PH4xe2x88x92xRx+ (Phosphonium) where X is as noted above. Anionic counterions groups connected to said cationic polar groups include F31  (fluoride), Clxe2x88x92 (chloride), Brxe2x88x92 (bromide), Ixe2x88x92 (iodide), and BF4xe2x88x92 (tetrafluoroborate).
Nonionic polar groups include various polyethers having from 1 to about 100 and preferably from about 2 to about 25 repeat units (n) include xe2x80x94Oxe2x80x94(CH2CH2O)nxe2x80x94H (poly(ethylene oxide)), xe2x80x94Oxe2x80x94(CH(CH3)CH2O)nxe2x80x94H (poly(propylene oxide)), various polyether copolymers, carbonyl, carboxyl, nitrile, thiol, or cyano, or xe2x80x94OH (hydroxyl).
Naturally, when a cationic polar group is utilized, it is utilized in conjunction with an anion to form a cation-anion salt, and conversely when an anion end group is utilized it is utilized in conjunction with a cation end group to form an anion-cation salt.
The type of polar group bonded covalently to the polymer can also be of a mixed anionic/cationic type forming an amphoteric-type polymer. Examples include covalent bonded cationic amine groups and anionic surfactants such as set forth in McCutheon""s Volume 1: Emulsifiers and Detergents, North American Edition, The Manufacturing Confectioner Publishing Co., Glen Rock, N.J., 1999, hereby fully incorporated by reference.
Preferably, the polar group(s) are covalently bonded to the end(s) of the polymer; however, the polar group(s) can be covalently bonded at any location along the polymer chain (backbone). The number of polar groups bonded covalently to the polymer can be 1 to about 10 and preferably about 2.
The polar groups can be added by (i) end groups introduced through polymerization (from initiators or chain transfer agents), (ii) modification of aforementioned end groups in (i), (iii) specific reactions on the polymer such as grafting (examples are photografting, radiation grafting and oxidation), (iv) addition reactions (such as that produced by condensation of a polar group-containing isocyanate with a hydroxyl group on the polymer), (v) substitution or metathesis (for example, alkyl halide displacement with AgBF4), and (vi) preferably, esterification of a hydroxyl group with sulfuric acid. Such reactions are known to the art and to the literature.
A preferred class of polymers are those derived from cyclic ethers generally containing from 2 to 5 carbon atoms in the ring and optionally substituted alkyl groups thereon containing from 1 to about 20 carbon atoms. Examples of such cyclic ethers include oxirane (epoxy) functionality such as epichlorohydrin, ethylene oxide, butyl glycidylether, and perfluorooctyl propylene oxide as well as alkyl substituted oxiranes having from 1 to about 20 carbon atoms or mixtures thereof; monomers having a 4-membered cyclic ether group such as oxetane, 3,3-bis(chloromethyl)oxetane, 3,3-bis(bromomethyl)oxetane, and, 3,3-bromo methyl(methyl)oxetane; monomers having a 5 membered cyclic ether group such as tetrahydrofuran, tetrahydropyran, and 2-methyltetrahydrofuran; and the like. Still other suitable monomers include 1,4-dioxane, 1,3-dioxane and 1,3-dioxalane as well as trioxane and caprolactone. A preferred polymer is derived from fluorosubstituted short carbon chain oxetane monomers as will be more fully discussed hereinbelow.
A class of preferred polymers include the various acrylic polymers such as for example, the various poly(alkyl acrylates) or the various poly(alkyl methacrylates) wherein the alkyl portion has from 1 to 18 carbon atoms with 1 to 4 carbon atoms being preferred and wherein the xe2x80x9cmethxe2x80x9d group can be substituted by a C2 to C4 alkyl. Still other suitable acrylic polymers include the various hydroxyl substituted poly(alkyl acrylates) and hydroxy substituted poly(alkyl methacrylates) wherein the alkyl group is as noted immediately above. Such polymers generally have from about 2 to about 100 repeat units and desirably from about 2 to about 10 or 20 or 30 repeat units. The preparation of such acrylic polymers is known to the literature and to the art. Example of suitable acrylate monomers include ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, phenyl acrylate, nonylphenyl acrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, methoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, ethoxypropyl acrylate, 2(2-ethoxyethoxy)ethyl acrylate, and the like. Especially preferred acrylate monomers include butyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate, and the like. Hydroxyl alkyl acrylates and methacrylates include hydroxyethyl and hydroxy propylacrylates and methacrylates, and the like, and are also preferred. Examples of still other acrylates are set forth in U.S. Pat. No. 5,055,515, hereby fully incorporated by reference.
Another class of polymers are those derived from vinyl substituted aromatics having a total of from about 8 to about 12 carbon atoms such as styrene, alpha-methyl styrene, vinyl pyridine, and the like, and copolymers thereof such as those made from conjugated dienes having from 4 to about 12 carbon atoms such as butadiene, isoprene, and the like. The Rf group is generally located on the ring compound. Such polymers can generally have from about 2 to about 100 and desirably from about 2 to about 10 or 20 or 30 repeat units. The preparation of such polymers is known to those skilled in the art as well as to the literature.
The polymer can also be a polyester. Polyesters are generally made by the condensation reaction of one or more dicarboxylic acids, containing a total of from about 2 to about 12 carbon atoms and preferably from about 3 or 4 to about 10 carbon atoms and include aliphatic as well as aromatic acids, with glycols or polyols having a total of from about 2 to about 20 carbon atoms. Polyesters can also be made by the ring opening polymerization of cyclic esters having from 4 to about 15 carbon atoms such as caprolactone, and the like. While numerous types of polyesters exist, such as set forth herein below, preferred polyesters include poly(ethylene terephthalate), poly(butylene terephtalate), and the like. The preparation of polyesters is well known to the art and to the literature.
The polyamides constitutes another class of polymers which can be utilized. The polyamides are made from cyclic amides having a total of from about 4 to about 20 carbon atoms such as polyamide 4 (polybutyrolactam), polyamide 6 (polycaprolactam), polyamide 12 (polylauryl lactam), or polyamides made by the condensation reaction of a diamine monomer having a total of from about 4 to about 15 carbon atoms with a dicarboxylic acid having from about 4 to about 15 carbon atoms such as polyamide 6,6 (a condensation product of adipic acid and hexamethylenediamine), polyamide 6,10 (a condensation product of sebacic acid and hexamethylenediamine), polyamide 6,12, polyamide 12,12, and the like with polyamide 6,6, and polyamide 6,12, being preferred. Such polyamides often have from about 2 to about 100 and desirably from about 2 to about 10 or 20 or 30 repeat units. The preparation of such polyamides is well known to the art and to the literature. Examples of the above polyamides as well as others are set forth in U.S. Pat. No. 5,777,033, which is hereby fully incorporated by reference.
The polysiloxanes still constitute another class of polymers which can be utilized in the present invention. The polysiloxanes are generally made from dihydroxysilane which react with each other by dehydration and dehydrochlorination. The side groups of the monomers are generally an alkyl having from 1 to about 20 carbon atoms. The number of repeat groups of the polysiloxanes is generally from about 2 to about 100 and desirably from about 2 to about 10 or 20 or 30. The preparation of the polysiloxanes is well known to the art and to the literature. Examples of suitable polysiloxanes are set forth in U.S. Pat. No. 4,929,664, which is hereby fully incorporated by reference.
The preparation of polyurethanes generally proceed in a stepwise manner as by first reacting a hydroxyl terminated polyester or polyether with a polyisocyanate such as a diisocyanate and optionally, subsequently chain extending and/or crosslinking the same. The polyether monomers of the intermediate can generally have from 2 to about 6 carbon atoms whereas the polyester intermediates can be made from diols and dicarboxylic acids as noted herein above with regard to the preparation of the various polyesters. Suitable diisocyanates generally have the formula R(NCO)X where X equals 2, 3 or 4 with 2 being preferred. R can be an aliphatic, an aromatic, or combinations thereof having from about 4 to about 20 carbon atoms. Such polyurethanes generally have from about 2 to about 100 and desirably from 2 to about 10 or 20 or 30 repeat units. The preparation of polyurethanes are well known to the art and to the literature. Examples of suitable polyurethanes are set forth in U.S Pat. No. 4,975,207, which is hereby fully incorporated by reference.
As noted above, desired fluorine containing polymers are those wherein the repeat units are obtained from cyclic ethers. Polymerization of such ethers generally proceeds by a cationic or an anionic mechanism. A desired fluorine containing polymer of the present invention is an oxetane polymer containing fluorinated side chains. The monomers as well as the polyoxetanes can be prepared in a manner as set forth herein below, and also according to the teachings of U.S. Pat. Nos. 5,650,483; 5,668,250; 5,688,251; and 5,663,289, hereby fully incorporated by reference. The oxetane monomer desirably has the structure 
wherein as noted above, n is an integer from 1 to about 3 or to about 6 and Rf, independently, on each monomer is a linear or branched, unsaturated, or preferably saturated alkyl group of 1 to about 7 carbon atoms with a minimum of 25, 50, 75, 80, 85, 90 or 95, or preferably perfluorinated i.e. 100 percent of the H atoms of said Rf being replaced by F, and optionally up to all of the remaining H atoms being replaced by I, Cl or Br. Rf desirably has from 1 to about 5 or 6 carbon atoms and preferably contains 2 3, or 4 carbon atoms. Rf can either contain a linear alkyl group or a branched alkyl group. When it is a branched group, the main chain contains from 1 to 7 carbon atoms and each branch chain can contain up to 3 carbon atoms as well, or the main chain contains from 1 to 6 carbon atoms and each branch chain independently has 1 or 2 carbon atoms, or the main chain contains from 2 to about 4 carbon atoms and each branch chain independently contains 1 or 2 carbon atoms. R is an alkyl from 1 to 6 carbon atoms with methyl or ethyl being preferred.
Preferably, the Rf group is present on the monomer used to prepare the polymer, but the Rf group can be added after the polymer is formed. For example, a typical reaction scheme involves the condensation of a commercially available Rf alcohol with a carboxylic acid group pendant or side chain on the polymer backbone.
The above polymers derived from the noted oxetane monomers generally have repeat units of the following structure 
where n, Rf, and R are as described above. R1 is an alkyl having from 1 to about 18 carbon atoms and is generally derived from a diol used in preparing the polymer. As noted above, polymers of formulas 3A and 3B are obtained by cationic polymerization.
The average degree of polymerization (DP) of polyoxetane (polymer) of the fluorinated polyoxetanes is generally from about 1 to about 500, desirably from about 2 or 3 to about 50 or 100, and preferably from about 4 to about 10, 20, or 30.
The hydroxyl groups can be converted to other polar groups through subsequent chemical reaction in a manner as noted above. Preferably, the hydroxyl groups can be converted to sulfate by esterification with fuming sulfuric acid.
While the following representative examples relate to the preparation of specific FOX (fluorooxetane) monomers, (i.e. mono 3-FOX, mono 7-FOX, and bis 3-FOX). Other mono or bis FOX monomers can be prepared in a similar manner.